title: Mapping IS6110 in high-copy number Mycobacterium tuberculosis strains shows specific insertion points in the Beijing genotype.
abstract: BACKGROUND
  Mycobacterium tuberculosis Beijing strains are characterized by a large number of IS6110 copies, suggesting the potential implication of this element in the virulence and capacity for rapid dissemination characteristic of this family. This work studies the insetion points of IS6110 in high-copy clinical isolates specifically focusing on the Beijing genotype.
  
  
  RESULTS
  In the present work we mapped the insertion points of IS6110 in all the Beijing strains available in the literature and in the DNA sequence databases. We generated a representative primer collection of the IS6110 locations, which was used to analyse 61 high-copy clinical isolates. A total of 440 points of insertion were identified and analysis of their flanking regions determined the exact location, the direct repeats (DRs), the orientation and the distance to neighboring genes of each copy of IS6110. We identified specific points of insertion in Beijing strains that enabled us to obtain a dendrogram that groups the Beijing genotype.
  
  
  CONCLUSIONS
  This work presents a detailed analysis of locations of IS6110 in high-copy clinical isolates, showing points of insertion present with high frequency in the Beijing family and absent in other strains.
authors.affiliation: Grupo de Genética de Micobacterias, Departamento de Microbiología, Medicina Preventiva y Salud Pública, Universidad de Zaragoza, C/ Domingo Miral sn, 50009, Zaragoza, Spain.
authors.forename: Henar
authors.initials: H
authors.lastname: Alonso
authors.forename: Sofía
authors.initials: S
authors.lastname: Samper
authors.forename: Carlos
authors.initials: C
authors.lastname: Martín
authors.forename: Isabel
authors.initials: I
authors.lastname: Otal
mesh_terms: D002874:Chromosome Mapping; D016000:Cluster Analysis; D004251:DNA Transposable Elements / Q000235:genetics*; D018628:Gene Dosage / Q000235:genetics*; D005838:Genotype; D009169:Mycobacterium tuberculosis / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics; D013045:Species Specificity
chemical_list: D004251:DNA Transposable Elements